Deviating from the Basic BSS

Quick question - after watching some of the videos on PS I noticed that the coaches often deviate from the SHC for example and raise, say, pocket 66 from some middle position with one limper behind them etc....

Even though they give brief explanation as to why they do it, I'm still unable to make a proper call as to when I can deviate from the SHC and the strategy in general.

I thought that by following the strategy you should be on the safest side, yet again, you can frequently start action with various hands.

Can someone try to explain what is it you'd take into account when deviating and how / when to do it ? What are the benefits and how can we, the noobs, adopt such playing style ? (What is it we should look for?)

A lot of this is explained in more advanced strategy (silver, gold and platinum articles). It is for you to expand your game as you progess. You start by playing a basic but efficient game and as you progress you evolve, play more hands and learn how to play them. I would suggest you stick to the strategy that is available to you for the moment.